Wire connection, method, and connecting apparatus

ABSTRACT

Electrical connection is formed between one or more filminsulated wires and a terminal by crimping the terminal onto the end of the insulated wire(s), facing the end of the wire(s) and terminal so that they are co-planar, and ultrasonically welding commoning plate of conductive metal to the wire and terminal ends so that conducting path is formed through the conducting plate.

United States Patent 1 Mann, Sr. et al. 1 Jan. 9, 1973 541 WIRE CONNECTION, METHOD, AND 2,802,044 8/1957 Corne .29/630 F CONNECTING APPARATUS 2.816.275 l2/1957 6 [75] Inventors: Richard Charles Mann, Sr., whey; Glendm Henry Schwalm, 3,137,925 6/1964 Wahl ..29/630F Camp Hill, both of Pa. [73] Assignee: AMP Incorporated, Harrisburg, Pa. Primary Examiner-John Campbell 2 Assistant Examiner-D. P. Rooney [2 1 Juneu 1970 Attorney-Curtis, Morris and Safford, Marshall M. [21] App1.No.: 45,522 Holcombe, William Hintze, William .1. Keating, Frederick W. Raring, John R. Hopkins, Adrian .l. 52 us. c1 ..29/628, 29/630 A, 29/629, and Jay 29/630 F [51] Int. Cl ..H0lr 43/00, H05k [57] ABSTRACT [58] Field of Search ..29/628, 630 A, 629, 630 F, Electrical connection is formed between one or more 29/628 film-insulated wires and a terminal by crimping the terminal onto the end of the insulated wire(s), facing [56] References Cited the end of the wire(s) and terminal so that they are co-planar, and ultrasonically welding commoning UNITED STATES PATENTS plate of conductive metal to the wire and terminal 1,782,447 11/1930 Scranton ..29/630A ends so that conducting path is formed through the 2,535,881 12/1950 Schroeder ..29/630 F conducting plate. I 2,615,074 10/1952 Bronovicki 2,768,105 10/1956 Dittmore ..29/628 3 Claims, 18 Drawing Figures PATENTEU JAN 9 I975 SHEET 1 [IF 9 PATENTED JAN 9 I973 SHEEI 2 UF 9 PAIENTEll-llll 9 I973 SHEET 5 [IF 9 PATENTED JAN 9 I975 SHEET 7 BF 9 WIRE CONNECTION, METHOD, AND CONNECTING APPARATUS BACKGROUND OF THE INVENTION It is common practice to provide insulation on certain types of conductors in the form of a thin film of varnish-like material such as a poly-vinyl formal resin, or other polymeric material. Such insulating materials being commercially available under the registered trademarks FORMVAR, ISOMID, and FORMEX. Film-insulated wires are commonly used for coil windings, extremely fine wires being used for small solenoid or motor coils and relatively coarse wires, up to 14 AWG. being used for larger sizes of motors. The wires may be of either aluminum or copper and it is sometimes necessary to form electrical connections among aluminum and copper wires.

It is virtually impossible to mechanically remove or strip a varnish type insulation from a wire unless vigorous wire brushing or abrading is resorted to and processes of this type are not compatible with most production methods in which film-insulated wires must be terminated. Alternatively, film-type insulations can be removed from wires by the use of a suitable solvent but this chemical stripping method is again inconvenient and impractical as a production line process. Where the film-type insulation is relatively thin and the wires are not relatively coarse, insulation piercing crimped connections can be made to the wires by means of terminals having film penetrating grooves on their inner surfaces. The insulation piercing approach to the termination of film insulated wires has received wide acceptance but it is not always practical to use this method for coarse wires adapted to carry relatively high currents and having relatively thick insulating films thereon.

The present invention is directed to an improved electrical connection for film-insulated wires and particularly to such wires having relatively thick insulating films thereon which are not amenable to insulation piercing as a termination technique.

It is accordingly an object of the invention to provide an improved electrical connection for film-insulated wires. It is a further object to provide an electrical connection for film-insulated wires which does not require stripping of the insulation or penetration thereof by an insulation piercing crimp. A further object is to provide an improved apparatus for forming electrical connections among film-insulated wires and between such wires and an electrical terminal. A further object is to provide a method of electrically connecting film-insulated wires to each other and/or to a crimpable electrical terminal member. It is an additional object of the invention to form corrosive resistant electrical connections among aluminum and copper wire.

These and other objects of the invention are achieved in a preferred embodiment thereof which is briefly described in the foregoing abstract, which is described in detail below, and which is shown in the accompanying drawing in which: 7

FIG. 1 is a perspective view of a short section of a terminal strip, the terminals being of a type adapted to be used in the formation of electrical connections in accordance with the invention.

FIG. 2 is a perspective view illustrating 21 facing operation which is carried out during the formation ofa crimped connection in accordance with the invention.-

FIG. 3 is a perspective view illustrating a welding step during which a conductive plate is welded to the face of the crimped connection.

FIG. 4 is a perspective view of a crimped connection having a commoning plate on its face.

FIG. 5 is a view similar to FIG. 4 but showing the manner in which edge portions of the commoning plate are folded over the end of the crimped terminal.

FIG. 6 is a view taken along the lines 6-6 of FIG. 5.

FIG. 7 is a frontal view of a preferred form of apparatus in accordance with the invention.

FIG. 8 is a top plan view of apparatus of FIG. 7.

FIG. 9 is a fragmentary perspective view on an enlarged scale of the operating zone of the apparatus showing the crimping die and anvil, the milling cutter, the welding tip, and the commoning strip feed.

FIG. 10 is a sectional view taken along the lines 10- 10 of FIG. 8 showing the milling cutter and the manner in which it is supported for movement past a crimped connection.

FIG. 11 is a view taken along the lines 11-11 of FIG. 10.

FIG. 12 is a plan view, partly in section, showing details of the commoning strip feed means for feeding commoning strip material to the crimping zone.

FIG. 13 is a view taken along the lines 13-13 of FIG. 12.

FIG. 14 is a fragmentary view on an enlarged scale of the nose portion of the commoning strip feed means illustrating details of the strip shearing mechanism, this view showing the positions of the parts immediately after the beginning of a strip feeding cycle.

FIGS. 15, 16, and 17 are views similar to FIG. 14 but showing the positions of the parts at successive stages of the feeding and strip cutting cycle.

FIG. 18 is a fragmentary exploded perspective view of the nose portion of the commoning strip feeding means.

Referring first to FIGS. 1-6, an electrical connection between a plurality of film-insulated wires 2 and a terminal 6 is formed by crimping the sidewalls 10 of an open-U type terminal onto the ends of the wires. The terminals may be manufactured in the form of a continuous strip with each terminal being integral with a carrier strip 12 so that the strip may be fed towards the operating zone of a terminal applicator as will be described below. After crimping, the end of the terminal is faced by moving a rotating milling cutter 14 thereacross so that the ends of the wires will be coplanar with each other and with one end of the crimped terminal. Thereafter, commoning strip material 16 is fed to locate the leading end of the strip against the face of the terminal. The end portion of the strip is then ultrasonically or otherwise welded by a welding tip 18 to the terminal face. The strip is then severed so that a commoning plate 20 is welded against the end of the crimped termination and the projecting edges of this plate may then be folded over the end portion of the crimped terminal as shown at 22 to provide a smooth uninterrupted skirt. The termination may be insulated in any desired manner as by heat shrinking a plastic tube onto the terminal. In the finished crimped connection, the plate 20 is bonded as shown at 24 to the ends of the wires and the end of the terminal so that these members are electrically commoned notwithstanding the fact that the insulating film 4 remains on the wires.

Referring now to FIG. 7, the disclosed apparatus in accordance with the invention is mounted on a surface 26 which in turn is supported by vertical supporting members 28 and comprises a press generally indicated at 30 having a base or platen 32 and a horizontally extending upper arm 34. A reciprocal ram 36 is contained in the end portion of the arm 34 and is coupled to a ram in a terminal applicator generally indicated at 38. A crimping die 40 mounted on the lower end of the applicator ram is moved towards and away from an anvil 42 having base portion 44 which is suitably mounted on an applicator base plate 46. The crimping die 40 has converging and parallel forming surface portions as shown which bend the sidewalls 10 of a terminal inwardly and downwardly when the die moves toward the anvil as is well known to the electrical terminal art. The terminals are fed to the die by means ofa feed finger 62 which is reciprocated by a lever 66 actuated by a suitable cam on the applicator ram. The feed path for the terminal strip extends over a feed platform 64 which is integral with the applicator and which extends to the anvil so that the leading terminal of the strip will be located on the anvil at the end of each feeding operation as shown in FIG. 9.

During the crimping operation, the leading terminal of the strip, which is supported on the anvil, is severed from the carrier strip 12 by a movable shearing member 52 mounted in a suitable recess and a fixed block 54 on base plate 46. As best shown in FIG. 11, the movable shearing block is normally biased upwardly to the position of FIG. 9 by a spring 56 so that the carrier strip 12 will be fed through a transversely extending notch or slot 58 in shearing block 52. When the applicator ram moves downwardly a projection 60 on a depressor block 62, which is secured to the previously described applicator ram, engages the upper surface of the shearing block 52 to move it downwardly against the biasing force of spring 56 thereby to effect shearing of the terminal from the strip. The depressor 60 is contoured such that the wire or wires 4 can be inserted from the right as viewed in FIG. and positioned in alignment with the crimped terminal as shown in FIGS. 9 and 11.

The previously identified milling cutter 14 is mounted on the upper end of a shaft 68 which extends vertically through an opening 70 in the press platen 32 and the plates 46, 48. The lower portion 76 of this shaft is contained in a sleeve 74 and supported by suitable bearings as indicated at 78 and 80. Sleeve 74, in turn, is mounted in a shuttle, generally indicated at 72, in the form of a block which is slidably mounted on parallel rods 84 that extend between spaced-apart fixed blocks 86 on the underside of the supporting surface 26. As best shown in FIG. 10, the openings 70 are elongated to permit movement of the shaft 68 and the milling cutter rightwardly and Ieftwardly as viewed in FIG. so that the cutter will move past a crimped connection held between the die 40 and anvil 42. The shaft 68, 76 is coupled at its lower end to a flexible shaft 82 which in turn is coupled to the output shaft of an electric motor 83 mounted on the underside of the supporting surface 26.

Reciprocation of the shuttle 72 and the cutter 14 is effected by a piston rod 88 secured to the shuttle by a set screw 90 and extending from a tandem piston cylinder 92. The tandem piston cylinder 92 advantageously has separately controlled inlet and exhaust ports for each piston and controls are provided to gradually reduce the speed of movement of the piston rod when it approaches the end of its stroke in either direction. This arrangement is preferable to ensure smooth operation and even movement of the milling cutter past the crimped connection thereby to achieve a flat face on the crimped connection which is desirable for an effective weld between the wires and the terminal.

As shown in FIG. 7, a switch 96 may be provided on the lefthand side of the lefthand support block 86 to control the valves (not specifically shown) which admit or exhaust air from the piston cylinder 92. Other control switches may be provided at convenient locations to control other cylinders as will be described below.

The feeding mechanism 98 for feeding the metallic foil 16 to the crimping zone (FIGS. l2-17) comprises a frame plate 100 mounted on the upper surface of the support 26 and a face plate or cover plate 102 secured to the forwardly-facing side of the frame plate. The metallic foil is fed from a suitable endless source, such as a reel, through a feed groove 104 on the forwardly facing side of frame plate 100 by means of a reciprocable feed finger 106. This feed finger extends through a slot 108 in cover plate 102 and is forked on its end so that it straddles a rib 110. This rib, which is integral with the cover plate 102, extends along the length of the slot 108 and prevents the foil material from buckling during the feeding stroke.

Feed finger 106 is pivotally mounted on a pin 112 which extends through a recess in a block 114. This block is slidably mounted on a reciprocable feed rod or control rod 1 16 which extends parallel to the surface of cover plate 102 and is supported in bearing blocks 1 18, mounted on the cover plate. In order to prevent partial rotation of control rod 116, a flat surface 122 is ground on one side of the rod and bears against inserts 124, 126 in the bearing'blocks 118,120. The control rod thus extends through openings in the guide blocks or bearing blocks with its flat side against the insert blocks 124, 126.

The control rod is reciprocated by means of a piston rod 128 to which it is coupled at its righthand end as viewed in FIG. 12 extending from a piston cylinder 130 mounted on the cover plate 102.

Leftward motion is imparted to the reciprocable block 114 by means of the control rod 122 through a collar 117 which is fixed to the control rod on the lefthand side of the bearing block 120. As will be apparent from FIG. 12, upon leftward movement of the control rod from the position shown, the control rod will move independently of the feed block 114 until the collar 117 moves against the feed block 114.

Thereafter, and during the remainder of the stroke of i the control rod, the collar pushes the feed block leftwardly to advance the foil through the guide slot. The lost motion is provided between the collar and the feed block to permit the shearing mechanism to.be opened as will be described below.

After the foil material has been fed, the piston rod 128 and the control rod return to the position shown in FIG. 12 and the feed block 114 is returned to its start ing position by suitable return springs 115 extending between pins mounted on the feed block and the bearing block, see FIG. 7. The rightward movement of the feed block is limited by a suitable stop screw 132 which is threaded through the bearing block 120 as shown in FIG. 12 so that the amount of foil material fed can be precisely controlled by adjustment of this stop.

During return movement or rightward movement of the feed finger 106, it is dragged over the surface of the metallic foil and it is desirable to provide a detent or anti-backup means to prevent rightward movement of the foil with the feed finger. To this end, an anti-backup pawl 134 is provided in the bearing block 118 on a pivot pin extending through a recess 136 in the block. This anti-backup pawl is biased in a clockwise direction by a spring 137 and extends through an opening in the cover plate 102 to engage the strip material. This arrangement permits the strip to be fed leftwardly as viewed in FIG. 12 but prevents retractile movement of the strip by virtue of the fact that the pawl 134 digs into the strip when it is pulled rightwardly.

The strip material is fed past an end piece or nose piece 138 so that the leading end of the strip is positioned adjacent to the end of a crimped connection on the anvil. After the welding operation has been carried out it is thus necessary to shear the strip at a location immediately adjacent to the lefthand end of the nose piece 138. Such shearing is carried out by a movable shearing blade 142 (FIGS. 14-18) provided on the end of a block 143 mounted in a recess 140 in the lefthand end of the frame plate 98. The block 143 is pivotally mounted at its righthand end on a pivot pin 144 which extends through the frame plate and which is secured to one end of a lever 145. This lever extends downwardly as viewed in FIG. 14 and has a lost motion connection 146 at its end with the lefthand end of the control rod 116.

It is desirable to provide means to clamp the foil or strip material during the shearing operation in the form of a clamping shoe 147 mounted in a recess on the underside of block 143 by means of a pivot pin 148. The lefthand end of this clamping shoe is biased downwardly, that is counterclockwise with respect to pin 148, by means of a spring 149 which is interposed between the underside of the block and the top side of the clamping shoe. The extent of pivotal movement of the clamping shoe is limited by means of a set screw 151 which is threaded through the block 143 and adapted to bear against the righthand end of the clampin g shoe.

The operation of the shearing mechanism is as follows. At the beginning of the operating cycle, the parts will be in the position shown in FIG. 14 so that as the control rod 116 moves leftwardly to the position of FIG. 15, the block 143 will be swung upwardly about its pivotal axis 144 and the foil material is fed leftwardly by the feed finger 106 as described above. After the feeding stroke has been completed and the control rod reverses its direction and moves to the position of FIG. 16, the shearing block 143 is swung through a counterclockwise arc until the shoe 147 clamps the foil against the upper surface of the nose piece 138. During the final portion of the rightward stroke of the control rod 116, the block 143 is swung through a slight additional arc (FIG. 17) and the foil is sheared by the cooperative action of the edge 142 on the block and the edge 141 of the nose piece, the compression spring 149 being compressed to some extent during this final portion of the stroke.

The welding of the severed section of foil 16 against the face of the terminal is accomplished by a welding tip on the end of a rod 152 extending from a piston cylinder 154 mounted on the upper surface of the support 26. This rod is supported at 156 on an arm which is slidably mounted on a bracket 158 secured to the upper surface of the supporting table. High frequency vibrations in a plane parallel to the plane of the face of the terminal are imparted to the rod 152 by means of a coupling member 160 on the end of a transducer assembly 162. The righthand end of this transducer is supported above the upper surface of the support member 26 by suitable brackets 166, 168 and power is supplied to the transducer by conductors 164 extending from a power supply unit as shown. This arrangement for vibratory welding is described in more detail in the U.S. Pat. No. 3,056,192 of Jones and details of the transducer and power supply unit need not be presented here. It might be added that a model W 3'75 AW unit as supplied by Sonobond Corporation, of West Chester, Pennsylvania, can be used for carrying out this operation when mounted as shown.

The disclosed embodiment of the invention is particularly intended to form a common connection among wires extending from a stator wiring and to this end, a fixture or jig is provided at 170 on the supporting surface 26 to hold a stator. Advantageously, a wire trimming means 172 is mounted adjacent to the fixture 170 so that the wires can be trimmed prior to crimping of the terminal and so that their ends will be in alignment with each other. Additionally, a bending or folding means may be provided as shown at 174 for folding the marginal portions of the commoning plate 20 over the terminal as illustrated in FIGS. 4 and 5.

To briefly review the operation of the disclosed embodiment, the wires will first be presented to the wire trimming mechanism 172 and will then be located between the die and anvil. Thereafter the press 30 is actuated and the die 40 moves downwardly towards the anvil to crimp the leading terminal of the terminal strip onto the wires. At the same time, the shearing block 52 is depressed to sever this leading terminal from the carrier strip 12. The milling cutter 14 is then moved rightwardly to the limit of the stroke of the piston rod 88 and then leftwardly to its starting position thereby to face the end of the terminal and the wires so that they will be co-planar. The foil feeding mechanism is then actuated to feed foil material until the leading end of the foil is positioned or locked against the dressed end of the termination as shown in FIG. 15. The welding tip then moves against the foil and a brief surge of vibratory energy is imparted to the tip to effect bonding of the foil to the ends of the wires and the end of the terminal.

In the disclosed embodiment, it is intended that the die will remain in its bottom dead center position during the milling and welding operations to hold the crimped termination firmly and accurately during the welding operation. Advantageously, a magnetically actuated press in accordance with the teachings of J. R. Keller, Application Ser. No. 726,300 can be employed rather than a conventional mechanical press or pneumatic press. As explained in the above-mentioned Keller application, the dwell time of the ram can be accurately fixed for a magnetic press of the type described in the above-identified application.

The invention thus permits the achievement of a high quality electrical connection among film-insulated conductors in an extremely short time and without the necessity of a high degree of skill on the part of the operator. Since the commoning plate is welded to freshly machined surfaces (the end of the terminal and the ends of the wires), this plate becomes fused to all of the elements of the connection to provide a low resistance conductive path between them. Moreover, the invention can be used with a variety of metals or with combinations of metals; for example, the wires may be of copper or aluminum and the terminal will quite often be of brass although it may also be of aluminum. The invention is particularly advantageous where aluminum wires are being terminated in a brass or other non-aluminum terminal or where a copper and an aluminum wire must be electrically connected in a brass terminal. There is very little or no tendency towards corrosion of these mixed metal terminations because of the fact that the aluminum and copper wires are sealed from each other by the film insulation on their surfaces and the commoning plate, being bonded to the faces of the wires and the terminal, prevents any corrosive gases or liquids from coming in contact with the wires.

While the disclosed embodiment of the invention shows the welding means, the crimping means, and the milling cutter as being mounted in one operating zone, it is within the purview of the invention to mount one or more of the welding, milling, and crimping means at separate stations. Thus the crimping might be carried out at one station and the milling and welding operations carried out at a second station on a production line.

We claim:

1. A method of forming an electrical connection between a conductor and a terminal, said conductor having a varnish-type insulating coating thereon comprising the steps of:

crimping said terminal onto said conductor with one end of said terminal in substantial axial :alignment with the end of said conductor,

facing said end of said wire and said one end of said terminal whereby said ends are made flat and co planar,

welding a thin flat plate of conductive metal which has an area which is substantially equal to, and slightly greater than, the combined cross-sectional areas of said conductor and said terminal to said end of said conductor and said end of said terminal whereby electrical continuity is established between said wire and said terminal by said plate.

2. A method as set forth in claim 1 wherein said plate is welded to said conductor and said terminal by vibration welding.

3. A method of forming an electrical connection among a plurality of insulated conductors and a terminal, at least one of said conductors having a varnish type insulating coating thereon, said method comprising the steps of:

positioning said conductors in said terminal with the ends of said conductor proximate to one end of said terminal, mechanically crimping said terminal onto said conductors, milling said end of said terminal and said ends of said conductors whereby said ends are made flat and co-planar, and vibration welding a thin flat metal plate which has an area which is substantially equal to, and slightly greater than, the combined cross-sectional areas of said conductors and said terminal to said ends of said conductors and said end of said terminal thereby to establish electrical continuity among said conductors and said terminal. 

1. A method of forming an electrical connection between a conductor and a terminal, said conductor having a varnish-type insulating coating thereon comprising the steps of: crimping said terminal onto said conductor with one end of said terminal in substantial axial alignment with the end of said conductor, facing said end of said wire and said one end of said termInal whereby said ends are made flat and co-planar, welding a thin flat plate of conductive metal which has an area which is substantially equal to, and slightly greater than, the combined cross-sectional areas of said conductor and said terminal to said end of said conductor and said end of said terminal whereby electrical continuity is established between said wire and said terminal by said plate.
 2. A method as set forth in claim 1 wherein said plate is welded to said conductor and said terminal by vibration welding.
 3. A method of forming an electrical connection among a plurality of insulated conductors and a terminal, at least one of said conductors having a varnish type insulating coating thereon, said method comprising the steps of: positioning said conductors in said terminal with the ends of said conductor proximate to one end of said terminal, mechanically crimping said terminal onto said conductors, milling said end of said terminal and said ends of said conductors whereby said ends are made flat and co-planar, and vibration welding a thin flat metal plate which has an area which is substantially equal to, and slightly greater than, the combined cross-sectional areas of said conductors and said terminal to said ends of said conductors and said end of said terminal thereby to establish electrical continuity among said conductors and said terminal. 